液晶結晶形態與動力學的研究

Study of crystalline polymorphs and kinetics of crystallization of liquid crystals

張鎮榮(Jenn Rong Chang)

指導教授 ： 黃振球

元智大學/工程學院/化學工程與材料科學學系/碩士(1998年)

摘要

液晶由於具有獨特的性質而被廣泛的研究著，在此主要討論的是液晶的結晶性質。實驗中是以三種具有不同分子鏈長度與液晶相，但具有-CN強極性基的相似液晶類作為比較，藉以瞭解其間結晶性質相同與相異之處。結晶動力學的研究是以示差掃描熱卡計（DSC）做分析，並且利用光學顯微鏡來觀察結晶形態的變化與晶體的成長情形。在此我們發現到當結晶溫度的不同會造成液晶的結晶形態產生改變，晶體成長速率也會因為結晶溫度的升高而降低，液晶所具有的液晶相也發現會對於結晶行為產生某些程度的影響。因此我們認為成核趨動力的大小是產生不同結晶形態的主因之一。

關鍵字

晶體成長速率 ； 成核趨動力

並列摘要

There were many research for liquid crystal owing to the special quality of semi-crystal. In this paper we primarily study the character of crystal. We used three kinds of different molecular liquid crystals (n-OCB) with the same -CN group as our materials and tried to know the different crystallization pattern between them. In order to study the crystallization kinetic, we used DSC to analyze the different crystallization of the materials and POM to observe their crystallization pattern. The result shows that the crystal pattern will change in different crystallization temperature and the growth rate of the crystal will slow down when the crystallization temperature increases. At last, we believe that the nuclear driving force is the main reason for forming different pattern of the crystals.

並列關鍵字

crystallization kinetic ； nuclear driving force

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